1. Field of the Invention
The present invention relates to an apparatus for processing a color image and, more particularly, to an apparatus and method for inputting an image of a plurality of color data items, such as four color data items, yellow (Y), magenta (M), cyan (C) and black (Bk).
2. Description of the Related Art
Conventional image processing apparatuses for inputting and outputting Y, M, C and Bk data items perform no calculations or only predetermined calculations.
An automatic setting method referred to as automasking is utilized to set color correction conditions.
The above known arrangements have a disadvantage in that when yellow, magenta, cyan and black image signals (hereinafter referred to as YMCBk signals) used for one type of output printer are fed to another type of output printer so as to print an image, the color of an image output by the former printer differs from the color of an image output by the latter printer. It is impossible to determine color processing parameters when the YMCBk signals are employed. When there is a difference in color reproducibility between one output device and another, colors cannot be corrected by using the YMCBk signals. For example, as shown in FIG. 4, when YMCBk signals used for printer A are output by printer B, the color of a copy produced by the former printer differs from that of a copy produced by the latter printer.
In addition, in conventional printers, when four color data items, e.g., yellow, magenta, cyan and black, are superposed on each other on the same pixel, the toner and ink may be scattered, thus deteriorating image quality or decreasing a fixing capacity.
There are color image processing apparatuses which convert YMCBk or YMC signals into luminance signals, such as red, green and blue. Such image processing apparatuses perform no calculations or only predetermined calculations with respect to the YMCBk signals.
There have been occasions when YMCBk signals used for a certain output device are input, red, green and blue luminance signals must be output.